[ocaml-platform] Maintainer notifications for opam-builder -- and other opam-builder enhancements

[Thomas Gazagnaire]

> In general I would encourage anyone to help improve opam-builder. We already have a few suggested features in the issue tracket (for example Alain Frisch gave feedback tracked in https://github.com/OCamlPro/opam-builder/issues/17 ), but ideas for improvements can easily be very open-ended while the resources to implement those changes seem fairly scarce, so I think focusing on small things first and actually implementing them could be very productive.

Is there any hope to change the license? As a repository maintainer, I use/maintain/publish a lots of CI scripts and I also work on related topics, so AGPL make it impossible for me to contribute.

Best,
Thomas